The proposed research program includes four faculty-directed research projects representing a broad range of biomedically important disciplines: developmental biology, molecular biology and biochemistry. In the first study, the anatomical development of the two major rodent olfactory systems will be compared and contrasted; their individual and/or overlapping functions will be studied. Infant homing behavior in rats will be the primary behavioral test. The developmental biology project involves a study of the mechanism of atrophy and resorption of denervated regenerating limbs of the adult newt Triturus viridescens. The molecular biology research project is designed to identify conformational changes within the protein pigment of the purple membrane of H. halobium and to measure the rotational freedom of Bacteriorhodopsin within its lipid matrix. Details of the chronological relationships of phototransients that compose the photocycle will also be investigated. The lead toxicity studies are concerned with identifying dietary components, specifically trace metals, that influence lead retention and lead toxicity. In addition, the criteria used for the determination of lead toxicity will be examined.